Improve streaming from richer JSONL transcript events

[kunal0137]

Problem

Streaming can be cleaner and more accurate when it uses the richest reliable transcript events available instead of a weaker subset.

Scope

• Inspect a representative JSONL transcript from a real run.
• Compare all event types against what the app currently renders.
• Use better events for incremental text, tool lifecycle, progress, or final message assembly when they improve clarity.
• Keep a small fixture for regression checks.

Acceptance Criteria

• Streaming feels cleaner and more real-time.
• Useful JSONL event types are no longer ignored.
• The transcript does not become noisy or confusing.